Adefovir is a nucleoside analog with activity against a broad spectrum of retroviruses and herpes viruses, including important human pathogens such as HIV-1 and HIV-2, HSV-1 and HSV-2, and CMV. Nelfinavir is a selective, nonpeptide inhibitor of HIV protease with significant antiviral activity measured in cell culture and animal models of HIV infection. Phase I/II clinical trials of nelfinavir indicate that nelfinavir adminsitration leads to substantial decreases in plasma concentrations of HIV-1 RNA and increases of CD4-lymphocytes. The purpose of this study is to evaluate novel, multiple drug combinations with adefovir dipivoxil as par tof a triple combination therapy with nelfinavir and reverse transcriptase inhibitors in pediatric clinical use. The safety and tolerability, the antiviral and immunorestorative effects of the two groups will be compared.